Vol. XXII 

 1905 



Recent Literature. A-'K'k 



against it. It may stand as at least a suggestion worthy of serious con- 

 sideration. We confess being to a large degree in sympathy with it and 

 with much of the author's comment thereon. It is to be noted, however, 

 that in the case of closely related subspecies, the normal range of indi- 

 vidual variation might make it impossible to properlv refer occasional 

 specimens without a knowledge of the locality of their origin ; and prob- 

 ably more than once has the mistake been made of recording a western 

 race from an eastern locality on the basis of an aberrant eastern bird. 



In regard to slightly differentiated insular forms, it was at one time 

 quite generally held that as there could not be actual intergradation 

 between such forms and the mainland stock (in the case particularly of 

 the smaller land mammals), owing to their physical isolation, it was bet- 

 ter to recognize such forms as species than as subspecies, since the latter 

 are either known or assumed to intergrade through the continuous range 

 of the geographical forms of a widely dispersed species. Of late, how- 

 ever, this method is being largely abandoned, slightly differentiated 

 insular forms being now very generally treated as subspecies. 



Now that Mr. Clark has voiced the 'contempt' long held by morpholo- 

 gists, physiologists and embryologists respecting the work of systematic 

 zoologists, the retort may be made that the contempt is, to a certain 

 extent, mutual, and perhaps to some degree not without cause on both 

 sides. But only the most narrow-minded of either class can fail to recog- 

 nize good work outside of their own circumscribed specialities. A cer- 

 tain class of the ' section-cutters ' take little account of the broader 

 relations of animals to their surroundings, and in their histological and 

 statistical investigations have been known time and again to work on a 

 lot of heterogeneous material under the impression that it was all com- 

 parable and homogeneous, — as conspecific while in some instances it 

 was not even congeneric, to say nothing of generalizations under statis- 

 tical methods based on incongruous and non-comparable material. 



" 4. Characters -which -will not distinguish corresponding ages or sexes 

 of ttvo forms ought not to be made the basis 0/ a new name. 



"This seems so self-evident, I hesitate to state it, but as it may prove 

 the one on which we can all agree I mention it, although it is no more 

 obvious to me than principles one and three. Of course this does not 

 mean that the characters must be present in both sexes at all ages. On 

 the contrary, the characters may be present only in one sex or at a par- 

 ticular time of life, but they must distinguish from the corresponding sex 

 or age." 



The author's comment under 'Principle 4' to some extent explains 

 its intent, without which it would be quite absurd. Thus: "Char- 

 acters which will not distinguish corresponding ages or sexes of two 

 forms," etc. ; but he evidently does not mean this to apply to species 

 in which, while the adult males are too distinct to be confounded bv the 

 merest tyro, the females and young cannot be positively discriminated 

 by the expert; or in other cases where, while the females are distinguish- 



